It‘s appear the CPRI LLOF alarm in the TMU LOG, you can check the indicator of frame error rate. Still want to advice customer take the necessary spare parts replacement , optical module and RRU. not only switch. Use to locate the problem gradually replaced

Root Cause

Incorrect physical connection of CPRI port in multi-cell mode, the red area, it must to replace

Solution

And for such BBU redundancy solution, it is
required that the RXU chain topology should be the same, that is to say the
chain should to be connected to the same Number of CPRI port Active BBU and
Standby BBU.